Issue 1804: March 19, 2025

CDC published Human Cases of Highly Pathogenic Avian Influenza A(H5N1)—California, September–December 2024 on March 13 in MMWR. A portion of the summary appears below. 

Persons with occupational exposure to highly pathogenic avian influenza (HPAI) A(H5N1) virus–infected dairy cattle are at increased risk for infection. . . .

During September 30–December 24, 2024, a total of 38 persons received a positive test result for HPAI A(H5N1) viruses in California; 37 were dairy farm workers with occupational exposure to sick cows. One, a person aged <18 years with an undetermined exposure, was the first pediatric patient detected with influenza A(H5) infection in the United States. . . .

Public health agencies should investigate influenza-like illness or conjunctivitis in workers with occupational exposure to animals infected with HPAI A(H5N1) virus. Thorough investigations of all human HPAI A(H5N1) virus infections are necessary to identify potential exposure sources, including monitoring the virus for concerning genetic changes that indicate the potential for person-to-person transmission.

Access the MMWR article in HTML or PDF.

Related Link

• CDC: MMWR main page providing access to the MMWR family of publications

Celebrated April 7–11 this year, Adolescent Immunization Action Week (#AIAW25) urges parents, healthcare providers, and adolescents to keep teenagers up to date. Visit Unity’s AIAW campaign page for social media-ready materials to draw attention to improving coverage. Use the hashtag #AIAW25 to spread the word.



Unity’s password-protected toolkit includes graphics and a short article about the observance for emails, newsletters, or blogs. To access this, sign up at the bottom of the AIAW25 web page.

Immunize​.org corrected an error on the Immunizations for Babies: A Guide for Parents. The small print indicating the timeframe for the final Hib vaccine dose listed on the 12 months and older row displayed the wrong age range for administration. It was corrected to display the correct range of 12–15 months.

Related Links

• Immunize​.org: Clinical Resources: Parent Handouts main page
• Immunize​.org: Clinical Resources: Schedules for Patients main page
• Immunize​.org: Vaccines A–Z: Haemophilus influenzae type b (Hib) main page
• Immunize​.org: Clinical Resources A–Z main page, where you can filter by topic, vaccine, language, or other criteria

For week 10, ending March 8, CDC’s Weekly Influenza Surveillance Report, FluView, showed influenza-like illness activity at high to very high levels in 25 of 39 reporting jurisdictions. This season is a high-severity season for people of all ages. During week 10, 4.3% of outpatient visits were for influenza-like illness, well above the epidemic threshold of 3.0% for the fifteenth consecutive week. Twenty pediatric deaths associated with seasonal influenza virus infection were reported during week 10, bringing the 2024–25 season total to 134 childhood deaths due to influenza.



RESP-NET
Visit the CDC Respiratory Virus Hospitalization Surveillance Network (RESP-NET) for weekly reports of hospitalizations due to three vaccine-preventable seasonal respiratory viruses: COVID-19, influenza, and RSV. COVID-19 vaccination is recommended for everyone age 6 months and older; RSV vaccination at this point in the season is recommended for certain high-risk adults age 60 through 74 and all adults age 75 years and older. RSV immunization of infants and certain high-risk toddlers with nirsevimab (Beyfortus, Sanofi) is recommended until the end of March.

Influenza Vaccination Dashboard
CDC's Weekly Flu Vaccination Dashboard shows that, as of March 1, 37.9% of pregnant patients had received influenza vaccination, although coverage rates differ widely by racial and ethnic group. Vaccination coverage was highest among non-Hispanic Asian pregnant patients (53.3%) and lowest among non-Hispanic Black pregnant patients (26.2%). Vaccination during pregnancy is important to protect both mother and infant from the consequences of influenza infection.

CDC recommends everyone age 6 months and older get annual influenza vaccination. Given the high levels of circulating influenza across the country, vaccination remains important for all eligible, unvaccinated people.

Identify pharmacies in your area that may offer influenza and COVID-19 vaccines by entering a zip code in the VaccineFinder on Vaccines.gov or Vacunas.gov.

Related Links

• CDC: Weekly National Flu Vaccination Dashboard main page
• CDC: FluView main page
• CDC: RESP-NET main page
• Immunize​.org: free clinical resources and patient handouts related to influenza
• Immunize​.org: Vaccines A–Z: Influenza main page

NFID.org provides resources in its NFID Resource Library to help increase awareness and prevent further spread of measles. Measles resources from NFID include:

• Frequently Asked Questions About Measles (updated based on common questions about current outbreaks)
• Measles Awareness: Sample Social Media Posts and Graphics
• Contagious Chronicles: Measles Alert (consumer-friendly audio recording)
• Combating the Resurgence of Measles and Other Preventable Diseases (on-demand webinar for healthcare professionals)
• Shareable Videos: 
  • 5 Things You Need to Know About Measles in 30 Seconds (30 seconds)
  • This Is How Easy It Is to Spread Measles (15 seconds) 
  • Measles . . . Don’t Come Back (17 seconds)
• Infographics: 
  • 5 Things You Need to Know About Measles 
  • 3 Things Parents Need to Know About Measles and Vitamin A 

Share widely to help combat misinformation and promote measles vaccination.

Immunize​.org's Influenza Vaccination Honor Roll recognizes facilities that take a stand for patient safety by implementing policies requiring healthcare personnel influenza vaccination. Immunize​.org welcomes Harris Health, Bellaire, TX, to our honor roll.

• Eligible organizations: hospitals, long-term care facilities, medical practices, pharmacies, professional organizations, health departments, and other government entities
• Requirements:
  • Your policy must require influenza vaccination for all staff
  • The application must describe measures to prevent transmission of influenza from unvaccinated personnel to patients (e.g., masking for the entire shift)

• Immunize​.org: Honor Roll Honorees: Influenza
• About the Influenza Vaccination Honor Roll

This week, our featured episode from the Ask the Experts Video Series is titled Is RSV Vaccine an Annual Vaccination Like Influenza? The video highlights that RSV vaccines, which are recommended during pregnancy, for all adults 75 and older, and for high risk adults age 60 through 74, are currently approved and recommended only for a single dose. Revaccination is not recommended at this time.

The 1-minute video is available on our YouTube channel, along with our full collection of quick video answers to popular Ask the Experts questions.

Like, follow, and share Immunize​.org’s social media accounts and encourage colleagues and others interested in vaccination to do likewise.

• Facebook at ImmunizeOrg
• Instagram at ImmunizeOrg
• LinkedIn at ImmunizeOrg
• YouTube at ImmunizeOrg

Journalists seek out Immunize​.org experts to help explain vaccines to the public and policy makers. We help the media understand and communicate the complex work vaccinators do. Here is a recent citation.

• Contemporary Pediatrics: 2025 Immunization Update: Addressing Vaccine Hesitancy and Catch-Up Vaccinations (3/11/25)

These recent articles convey the potential risks of vaccine-preventable diseases and the importance of vaccination.

• New York Times: We Need a Reminder of What the Pre-Vaccine Era Was Like (3/13/25)
• FDA: Influenza Vaccine Composition for the 2025–2026 U.S. Influenza Season (3/13/25)
• New York Times: Where U.S. Measles Outbreaks Are Spreading (3/16/25)
• The Atlantic: His Daughter Was America’s First Measles Death in a Decade (3/11/25)
• New York Times: What We Know About mRNA Vaccines (3/11/25)
• NPR: RFK Says Most Vaccine Advisers Have Conflicts of Interest. A Report Shows They Don’t (3/11/25)
• AP News: Researchers Are Learning the Trump Administration Axed Their Work to Improve Vaccination (3/11/25)
• ABC: CDC to Study Vaccines and Autism, Despite Several Studies Already Finding No Link (3/8/25)